Sony/Philips Digital Interface: digital audio format for consumer equipments. It’s the equivalent of AES 3 signal (used for professional equipments). It uses 75 ohm coaxial cable and RCA connector for max distances of 10 m. For lower distances at 15 m it’s used plastic optical fibre and TOSLINK connector. For distances up to 1 Km it’s used glass optical fibre with encoders and decoders needed for this type of transmission.